Outlet box



oct. 1s, 1932. H. s, ARNO, 1,883,457

OUTLET BOX Filed June 22. 1928 INVENTOR Patented Oct. 18, 1932 HARRY S. ARNOLD, F BROOKLYN, NEW YORK von'iinirr Box Application lcd June 22, 1928. Serial No. 287,380.

i This invention relates to outlet boxes, junction boxes and the like.

Special objects of the invention are to pro- 'vide a box for electrical wiring purposes illustrated, but it should be understood that the structure may be modified as regards this I disclosure without departure from the true and particularly for use in concrete structures, which will be easy to install; which will require but a single handling of the conduits, instead of several as heretofore; which will have the wires entered in such a Way that they can be drawn and fished practically without be of simple, inexpensive, and at the same time light butv strong rigid construction.

The foregoing and other desirable objects are attained in this invention by certain novel features of construction, combination and relations of parts as hereinafter ldescribed and broadly. claimed.

In the accompanying 'drawing forming `part of this specification, certain practical commercial embodiments of the invention are spirit and broad scope of the invention.

Fig. 1 is a broken cross-sectional view illustrating the box as incorporated in a concrete floorslab; Fig. 2 is a detached sectional view of the box showing the fixture stud and anchor bar as fastened on top ofthe box instead of inside as in the first view; Fig. 3 is an inside plan view of the box as shown in Fig. 2. The box shown is of octagonal shape at the lower or open end of the same, but differs from the usual form of' box in that the sides 5 of the same are inclined upwardly and inwardly, converging to a smallerl octagonal shaped top wall 6, which is shown formed as integral with the convergent and triangular shaped side walls. This structure lends itself readily to being formed in a punch press from a single piece of sheet metal, and because of its frusto' pyramidal shape, is particularly rigid and strong, enabling the use of light and inexpensive sheet metal, which can be drawn to this form `from the flat stock. The frusto pyr'amidal or conical form also ives the box a balance and a wide supporting ase, which prevents it from being easily fknocked over when placed on the forms.

bending; and which will Nail holes are indicated at 6' in the inclined side panels through which nails or other fastenings 7 may be driven into the form 8 for securing the boxes in their spotted positions, the inclination of these walls favors the driving of these fastenings as will be evident from the illustration.

KnockoutsQzand 10 are shown provided in the top and sides of the box for the passage of conductors, conduits orother parts.

In Fig. 1, a typical floor installation is illustrated, the slab being shown' atv 11 suitably reinforced at 12 and carrying the floor fill 13 and the finish ll 14. It will be noted that because of its upwardly convergent form, the box takes up considerably less space in the slab than a'full octagonal or straight sided box, and still is of the full size at the ceiling level. less concrete is displaced the slab is stronger than with the old style ox, and this is accomplished without sacrificing space at the open end where room is needed for making the wiring connections. To overcome any possibility of the box coming loose or pulling down out of its seat in the concrete, one or more anchorl ages may be provided, such as the bar shown at 15 and illustrated 1n the first view as extending through slots 16 in the sides of they box out into the mass of concrete surrounding the upper smaller end of the box. Where this bar is passe-d through the box in this fashion, it may be used as a hanger for a iixture stud such as that shown at 17, and comprising a hollow externally screw-threaded cup-shaped member cross-slotted at 18 in its upper widened base portion 19 for passage of the bar. `The slots 18 are shown made purposely wider than the bar, so as to permit the stud being adjusted in various ways and similarly the slots 16 in the sides of the box may be wider than the bar, so

that in first setting the bar .it may be adj usted angularly more or less relative to the box. A screw 20 is shown threaded'inl the lower closed end of the stud and as extending upwardly into engagement with the Abar so as to secure the stud in any desired position on the bar, 'saidscrew1 being accessible from below, so that a `stud may be adjusted for l instance, for centering a light in a line 0foutlets after the boxes have been installed. The inclination of the sides may vary, but a preferred anglel is such as that shown in which a continuation of theaxis of the conduit entered in one side of the box, as represented by the line 2l will pass below the edge of the opposite side of the box, so that wires may be fished and pulled straight out of the conduit without bending and without scraping the edges of the-box. This angle also is preferably such that the conduit entered perpendicularlylto the box Wall will stand at a wide obtuse angle to thel horizontal lines of conduit extendingtoand from the outlet box, to give the Wires an easy, gradual bend, so that they may be readily pulled, without scraping or, bruising the insulation. This feature is plainly shown in Fig; 1, where the horizontal stretches of conduit are indicated at 22 andthe bends 1t/.23 are shown as so gradual as lto offer practically no resistance to the pulling and lshing of the wires;

The upward inclination of the conduits extending from the box enables the horizontal sections of conduit 22 tovbe laid on top of the floor slab 1l and entirely within the floor iill 13. This is made possible in the illustrationby providing. wide angle conduit elbows 24, which extend up through the floor slab and have their horizontal portions exposed at the top of the slab for connection with the horizontal lengths of-conduit, or

by providing screwless couplings 25 extending up through the slab into position to receive the downwardly angled ends 26 of the horizontal sectionsof conduit.

The elbow form of connection shown at the left in Fig. l, may be provided by simply f putting a slight bend in short sections of conduit', which are threaded at one end to take a lock nut 27 at the outside of the box and a-screw bushing 28 at the inside of the box, such elbows being thereby secured fast 3 to the box before the box is nailed down on the form, so that they will become embedded with the box in the floor slab withtheir upper ends exposed at theV top of the slab. The upper exposed ends of' the elbows also may be threaded, if desired, to receive couplings for the horizontal sections of conduit, but as such threaded ends are'liable to become bruised in the course of the work carried on on top of the slab, they may be left plain and double ended threadless couplings, such as shown at 29, be used to couple the horizontal sections of conduit 22 with theexposed upper ends of the elbows.

lVhere threadless couplings are installed with the box as shown at the right in'Fig. 2, these will be of a length suflicient to reach to approximately the top of the slab, and they may be secured at the lowerend vin the box wall ,by a hollow coupling nut 30. At the time ofinstalling, the upper end of the coupling may be temporarily closed by a removable plug, but this is usually not necessary as a small amount of concrete entering the coupling at thetop of the slab may be easily knocked out when the conduit is to vbe attached. The contracting conical screw sleeve 31 which receives and clamps the' angled end 26 of the conduit, may be left only partly exposed at the top of the slab, so as not to be injured in the course of the work on the slab, and if necessary, the concrete of the slab may be chipped away about this clamping sleeve when. the conduit is connected therewith, enough room being made to enable the turning of the sleeve sufficiently to clamp the end of the conduit securely in the upper end of the coupling.

The many practical advantages of the invention will be apparent from the foregoing and ymay possibly be better appreciated by consideration of the following: When the position of the box is determined and the numl ber of connections thereto are known, the elbows or couplings are connected with the .sides of the box, and the box is then nailed down on the form. The anchor bar may be slipped through the slots in the top of the box before or after nailing the box down `on the form. If a fixture stud is employed, the same may be slipped into position on the bar before the box is placed on the form. If desired however, the iixture stud may be made as a hook, which can be engaged over the bar from inside the box after the box is installed and the forms have been removed. The slots for the bar may be located in a plurality of sides of the box as indicated in the detailed view in Fig. 2, so that if the upwardly angled connectors 24 or 25 for the conduit are in the way of placing the anchor bar in one position, the same may be located in another position, where it willl clear such connectors. After the first pour, indicated at 32, is made, and the steel reinforcement l2 is laid over the beams, the iioor slab concrete is tamped in place. lWhen this slab hardens, the box and connectors are embedded in their final position in the slab with the box properly anchored and supported in the slab and the upper -ends of the connectors accessible for connection of the different lengths of conduit therewith. The upper ends of the connectors project but slightly, if at all, at the top of the floor slab, and so do not interfere to any appreciable extent with the work on top of the slab. At the time when the ioor fill is to be made, the conduit for connecting the outlet boxes is measured and connected up with the connectors attached to the boxes and at such time, if any to'be connected up with the boxes. As the conduits are laid in the floor fill and not in thc-Hoor slab, no cracks or lines-of cleavage will appear in the arches when the floor dries out thoroughly. y

` If desired, the fixture stud may be mounted in the top of the box as indicated in Fig. 2, where the knock-out 9 in the top of the box has been punched out and the stud passed down through the top of the box, where it is securedon the inside of the box by a lock nut 33. In this location, the base of the stud is above the top of the box with the slotted or hooked portion 18 exposed so that the anchor bar 15 ma be placed in position any time before the sla is poured. v f

A suitable cover plate 34 may) be used to close the lower open end of the ox, it being shown as secured in place by screws 35 engaged with screw lugs 36 `integral with and turned in at the lower edges of the box. or

suitably attached to the side walls cf the box. Additional anchorage` or substitute for the anchor bar atthe top may be easily provided by constructing the lock nuts 27 for the con.- duit elbows as elongated bars extendinglbeyond the edges of the panels, as indicated in therein.'

Fig. 3, so asv to become embedded in the concrete surrounding the box. These anchorages are above the reinforcing steel and so can cui-ry the weight ofthe box and extraload of the fixture one or several of these anchor bars may be used, as considered necessary and they may be used with or without the cross bars 15.

What is claimed is:

1.y An outlet box of frusto pyramidal form open at the larger base end of the lsame and having convergent 'substantially trapezoidal side' walls extending Von inclines from the open base end of the box to a polygonal top wall, said substantially traizoidal side walls and polygonal top wall aving knockouts Q. 'An outletbox'of frusto pyramidal form open at the larger base end of the same and having convergent substantially trapezoidal side Walls, and a pol renal top wall, said substantially trapezoi a side walls and polygonal top wall having knockouts thereinv and certain of said inclined side walls having nailing openings therein permitting'fastenings to be driven from the outside perpendicu-l larly through said Walls at an angle into a foi-1n supporting the outlet box.

3. An outlet box of frusto pyramidal form open at the larger base end of the saine and having convergent substantially trapezoidal side Walls, a polygonal top wall, said substantially trapezoidal side walls and poly- H gontal top wall having knockouts therein,

said inclined walls having openings therethrough and an anchor bar extending through said openings and beyondand over the inclined sides of the-box.

open at the Alarger base end of the same and having convergent substantially trapezoidal side walls, and a polygonal top wall, said substantially trapezoidal side walls and poly- -gonal top wall having knockouts therein, said inclined walls having openings therethrough, an anchor bar extending through said openings aiid beyond the inclined sides of the box and a xture stud adjustably hung on the bridging portion of the anchor bar within the box.

5. As a new article of manufacture, a one piece sheet metal outlet box of substantially frusto pyramidal form, open at the base end of the pyramid and having convergent substantially trapezo'dal side walls united with a'polygonal top wall and provided with means for enabling entry of electric conductors therethrough.

6. As a new article of manufacture, an outlet box for eoncrete'floor slabs, comprising a shallow oneieee pressed sheet metal box structure of rusto pyramidal form, open at the larger' base end and having trapezoidal side walls extending from the base end of the box on convergent inclines and connected by a polygonal end wall, said pressed sheet metal box walls having integral knock-outs enabling wiring to be drawn from the boxen straight lines clear of the-base edges of the 4trape'zoidal side walls at the open end of the box.

7. As a new article of manufacture, an outlet box for Vconcrete floor slabs comprising a shallow one piece box structure open at one end and having convergent sides inclined directly from saidbopen end of the box and said convergent sides 4having removable knockouts for enabling wiring to be drawn into the box through said convergent sides.

8. As a new article of manufacture, an outlet box for concrete floor slabs comprising y a shallow one piece box structure open at one end and having convergent sides inclined directly from said o en end of the box, said l .In

convergent sides having removable knockouts for enabling wiring to be drawn into the box through saidy convergent sides and anchorage means projecting from the smaller end portion of said convergent sided box.

9. An outlet box for concrete construction comprising a box structure having knockouts in the sides of the same, conduit entered into the box by' way of one of saidlmockouts, a nut engaged on the conduit inside the box and a bar screwed on the conduit outside the box and engaging the box wall as a lock nut and projecting from the box wall to constitute an anchorage in surrounding concrete.

In testimony whereof I aiiix my signature.

HARRY S. ARNOLD.

4. An outlet box of frusto pyramidal form 

